The present invention relates generally to providing H.248 protocol capabilities for a media gateway (MG) to other media gateway controllers (MGCs) in addition to the media gateway controller that owns the media gateway.
In the architecture defined by the Media Gateway Control (MEGACO) IETF Working Group, a typical H.248 model comprises media gateways (MGs) focusing on media translation and media gateway controllers (MGCs) focusing on call signaling and call processing functions. Currently, media gateways are controlled by and associated with a single media gateway controller.
Voice-over IP (VoIP) calls, sometimes referred to as Internet telephony, have both a call signaling path and a bearer path. The call signaling path transfers call control data necessary to setup, connect and process a call. The bearer path is the actual voice data connection over which a conversation may take place. For many services call processing functions must be able to tap into the bearer path in order to detect specific events. However, the bearer path may only be accessed at specific points by specific nodes. In a typical VoIP call it is possible that several media gateway controllers are linked in the call signaling path while only two media gateways are in the bearer path. A media gateway port may have only one associated media gateway controller. Thus, if there are more media gateway controllers involved in a VoIP call than media gateways some of the media gateway controllers will not have access to bearer path event information normally provided by the MGC to MG protocol.
The present invention provides intermediate media gateway controllers with H.248 control reach through capability to a media gateway in the bearer path. Providing such capability eliminates the need to haul bearer paths unnecessarily to specific nodes just to monitor for DTMF tones or other bearer path information including detection of facsimile or data modem communications. By leaving the bearer path alone and providing H.248 control reach through capability to other media gateway controllers, the network operates more efficiently.
In accordance with a first embodiment of the invention is a method of providing the H.248 capabilities of a media gateway that is serving as one endpoint of a bearer path to a foreign media gateway controller for the purpose of providing bearer path access to the foreign media gateway controller. In typical call setup messaging, an answer message is modified to include a parameter requesting H.248 protocol capability. The owning media gateway controller sends a call control message to the foreign media gateway controller providing data pertaining to the media gateway. Using this data, an H.248 connection between the foreign media gateway controller and the media gateway is opened. The foreign media gateway controller can then monitor the bearer path associated with the media gateway.
In accordance with a second embodiment of the invention is a method of providing the H.248 capabilities of a media gateway that is serving as one endpoint of a bearer path to a foreign media gateway controller for the purpose of providing bearer path access to the foreign media gateway controller. A call control message is sent from the foreign media gateway controller to the owning media gateway controller which contains a parameter requesting notification of a specific event if the specific event should occur in the bearer path. The owning media gateway controller sends a request message to the media gateway which indicates the specific event of interest. When the requested event is detected, the media gateway sends a message indicating detection of the specific event to its owning media gateway controller. The owning media gateway controller then sends a call control message containing a parameter indicating detection of the specific event to the foreign media gateway controller. This implementation has the advantage of permitting the owning media gateway controller to act on the event before informing the foreign media gateway controller. This action might include deciding not to inform the foreign media gateway controller, to disconnect the call controlled via the foreign media gateway controller, or other actions.
An additional embodiment of the present invention is used to manipulate the bearer stream path for a remote media gateway. This is required to support changes of the near end connection endpoint address for the execution of services such as credit card, advice of charge, etc.